In a CMOS MEMS micro system, various methods for the release of MEMS devices exist. One of the methods is to remove a sacrificial material by a wet etching process using hydrofluoric acid (HF). The use of vapor phase HF (vHF) etching provides even faster and more complete removal of the sacrificial material than liquid phase HF. However, vHF is extremely corrosive and can damage inter-metal dielectrics of typical CMOS circuits, which are not resistant to vHF.